Treatment of fluids with comminuted solids



Dec. M, i948. B. F. WOBKER TREATMENT OF FLUIDS WITH COMMINUTED SOLIDSFiled Jan. 2, 1948 ATTORNEYS Patented Dec. 14, 1948 TREATMENT or FLUIDSWITH COMMINUTED somos Burle F. Wobker, Mission, Kans., assignor toPhillips Petroleum Company, a corporation of Dela- Ware This inventionrelates to the treatment of organic fluids with solid contact materials.In one specific embodiment the invention has. Aparin'cular applicationto the catalytic treatment of hydrocarbons wherein a finely dividedsolid catalystis employed which becomes coated with carbonaceous matter,which matter is periodically removed from the catalyst byoxidation. The.invention has particular though not exclusive utility in thecatalytic'cracking of hydrocarbon oils to form lower boilinghydrocarbons, and will be described with .specicjreference thereto inapreferred embodiment.

The cracking o .hydrocarbons in the presence of rcatalysts has long beenknown. :One 4of the standard methods is to deposit the particles ofcatalyst in the 'form of 'a lstationary bed within va reaction `vesseland to pass the charge stock, preheated to cracking temperatures,'through the bed of `catalyst under conditions effecting the desiredYcrac-king reactions. When .a gas oil, for example, is being cracked toform gasoline, acertain other products are also formed including lightgases and fa very heavy carbonaceous material which Vis deposited on thecatalyst particles and which is Yfrequently designated as cokej althoughthis latter material probably consists of a mixture of free carbon withhydrocarbons of yhigh molecular weight having 4a low hydrogen to carbonratio. This deposit causes what fisv apparently ia loss in activity ofthe catalyst, 4as evidenced by `a decrease in `production of desiredproducts, and after va period of time the extent of Yreaction becomessufficiently impaired ias to require fa stopping vof the crackingreaction for the purpose vof reactivating the catalyst. 'To this end theflow of hydrocarbon vapors is stopped, the cataylst bed is `purged withsteam or other inert gas, and an roxygencontaining gas, such as air, isthen passed through thecatalyst bed to burn 01T the `carbona'ceousdeposits 'and thus' reactivate the catalyst. rIlhis reactivation forregeneration treatment must be conducted with considerable caution inorder to avoid overheating the catalyst, since most silice'ous :crackingcatalysts cannot withstand temperatures-above vabout 1150 F. withoutbeing `.permarrently rimpaired in activity, while even'the most ruggedcatalysts, lsuch las bauxite, must `not be allowed to attain atemperature in Aexcess of 1400 to 1500" F, during reactivation.Afterfpart or all of the carbon has been removed lthe :chamber `islpurged of oxygen-containing gases 4and the catalyst bed .is againemployed Dior the cracking reaction. When `using .such fa'"stationaryfbedat Application January 2, 1948, Serial No. 222 111Claims. (Cl. 19a-.52)

least two catalyst :chambers are ordinarily employed so that one isalways available for onstream processing :How while the other is beingreactivated.

More recently there have come into common use the so-called mobilecatalyst systems in which the catalyst is caused to flow continuously ina cycle which includes iiow through a reaction chamber and alreactivation chamber. There are two principal types, one being theso-called TCC process in which catalyst particles of considerable sizeare moved downwardly through the reaction chamber in the 'form of aslowly moving bed, and are then lifted by mechanical means to the top ofa regenerator through which they again ow in the form of a moving bed;the thus reactivated catalyst is then transferred to the top of thereactor forl vanother cycle. The other principal method is known as thefluid cracking process, in which the catalyst is employed in the form ofa line powder. This powdered catalyst is maintained in the reactor andin the regenerator Yas a suspension in gases, and is moved through the'system in a cycle which includes the reactor and the regenerator whilesuspended in various gaseous streams. The catalyst may either besuspended in the reactants andregeneration gas and carried upwardly oreven horizontally at about the same rate of ow as the gases, or it maybe maintained in the respective chambers in the form .of a uidizecl bed,the latter being more common. In the fluidized bed'method of operating,vrelatively large bodies of -catalyst `are maintained in thereactivation and the reaction 'chambers in an aerated condition, andcatalyst is continuously being added t-o `and .removed from each bed forpassage to the other chamber. The catalyst within each chamber is in aturbulent conditionsomewhat resembling a boiling liquid, and there thusexists within the vchamber a ldense turbulent phase of catalystsuspended in gases, above which is a gas phase containing a muchAsmaller amount of catalyst which happens to be carried out of the densephase bythe up-llowing gases. The gases leaving the chamber areordinarily passed through one or more cyclone separators or other meansfor separating thefresidual catalyst from .suspension in the gases.

I-n the .fluidized bed technique the ycatalyst .itself is relied onto'carry'the heat Iof regeneration :into 'the 'reaction chamber tosupply the `endothermic vheat of the vcracking reaction. In order toIcarry sufdcient heat, yand also in order `to minimize .overheating in4the reactivation zone, a

relatively large quantity of catalyst is continuously circulated ascompared to the minimum amount which would be required for effecting thedesired amount of cracking. Furthermore, because of the uniform mixingof just-introduced spent catalyst particles with the entire body ofcatalyst in the reactivation zone, the reactivated catalyst withdrawntherefrom is neces-A sarily a mixture of catalyst particles. in allsta-ges of reactivation, and has the same carbon content as the averageof all the catalyst within the reactivation zone. Thus, in a typicalexample,

catalyst having an average carbon content of 3` weight per cent will becontinuously withdrawn from the reactor and introduced into thereactivation zone; the average carbon content is therein lowered to 1per cent, and it is difficult or impractical to carry out thereactivation in such a way as to produce a reactivated lcatalyst With acarbon content appreciably lower. Similarly, the conversion is alwayscarried `out in the presence of a mixture of catalyst particles not onlyof low, but also intermediate and high ycarbon content, and necessarilythe average carbon content of the catalyst inthe converter is far aboveeven that of the reactivated catalyst introduced thereto. Thereis,however, an advantage over xed bed operation in that the catalyst inthe reactor is always of the same average activity and accordingly avery 'uniform product is obtained over a long period of time.

One of the principal drawbacks of a fixed bed type of operation lies inthe variation in catalyst activity from the beginning of a processperiod in a cycle to the end of that period. Thus, in the beginning whenthe catalyst has been freshly reactivated there may be practically nocarbon on the catalyst which Will accordinglyhave the greatest activity.As the reactivation proceeds the catalyst becomes less active due to thedeposition of coke, and it is economically necessary to continue theconversion until the activity has decreased quite considerably. Thisdecrease in activity not only results in a lowered per-passconversicnbut may also cause a marked change in product characteristics.IThe resulting variations in quantity and quality of product introduceoperating difficulties with respect to fractionation and with respect toproduct quality control.

It has heretofore been suggested to combine certain features of thestationary bed and fluidized bed procedures and this has beenaccomplished by merely providing a body of powdered catalyst in each oftwo chambers, together with suitable cyclone separators and other meansfor retaining the catalyst within the chambers, and then alternatingeach chamber on conversion and on reactivation, in exactly the samemanner as if a stationary bed of catalyst rather than a iluidized bedWere within each chamber. While better heat control and other advantagesare thus obtained, a number of the disadvantages of each method stillremains, including the decrease in catalyst activity just mentioned.

While the foregoing discussion has been di rected specifically towardcatalytic cracking of hydrocarbon oils, it will beunderstood that theproblems are similar for the various other conversions and treatments oforganic fluids which are carried out in the presence of solid contactmaterials, including catalysts, under conditions causing laydown ofcarbonaceous matter onthe ing off or otherwise. Examples ofsuclioonvcrsions are well known to those skilled in the art and includecatalytic reforming of gasoline-boiling-range stocks to improve theoctane number thereof, catalytic desulfurization of similar materials,dehydrogenation of paramns and/or oleflns either normally liquid ornormally gaseous, the cyclization or aromatization of hydrocarbonmaterials, various alkylations including the alkylation of aromatichydrocarbons and of phenolic compounds with olefins, alcohols and alkylhalides, catalytic dehydration of oxygenated organic materials, anddehydrohalogenation of organic halides, as well as the simple treatmentof organic fluids with solid adsorbents to remove a component therefromeither by simple adsorption or a combination of physical adsorption andkchemical reaction such as polymerization, the

latter combination effect being exemplified by the clay treating orrefining of cracked gasolines. The Fischer-Tropsch synthesis whereincarbon monoxide is reacted with hydrogen to `form hydrocarbons andoxygen-containing organic compounds in the presence of a powderedcatalyst such as reduced iron, may be performed in accordance with thisinvention, the catalyst which becomes deactivated by wax deposits beingreactivated not by oxidation but bytreatment with hydrogen at elevatedtemperatures, such as from reaction temperature up to 800 C. Theprinciples of the invention are broadly applicable not only to organicconversions wherein carbon deposits cause deactivation of'catalyst, butlikewise to any conversion or treatment of fluids by solid contactmaterials, which term includes among other materials any solid catalyst,under conditions that cause fouling of the Contact material in any wayresulting in decreased activity and requiring reactivation in order tomaintain an active contact material. For example, in the dehydration ofalcohols to form olens in the presence of silica gel, alumina, or activeclays, the activity of a used catalyst which has become hydrated can beincreased by merely heating at an elevated temperature to dehydratesame.

It is an object of the present invention to provide improvements in thetreatment of fluids in the presence of a mass of subdivided solidparticles which became deactivated and require reactivation. It isanother obje-ct of this invention to improve the operation of catalytichydrocarbon conversions. A further object of the invention is to effectthe treatment of hydrocarbons with a powdered catalyst. Yet anotherobject is to combine certain principles of the fiuidized bed techniqueand the fixed bed technique in the catalytic conversion of hydrocarbonsin such a way as to obtain further advantages not available by thepractice of either method alone. A still further object of the inventionis to employ intermittent conversion and reactivation steps within asingle chamber while yet maintaining a substantial constant catalystactivity through the conversion step. A further object is to minimizethe circulation of powdered catalyst through a conversion system of thetype described. Yet another object is to obtain improved carbon removalfrom a powdered catalyst. Further objects and advantages of theinvention will be apparent, to one skilled in the art, from theaccompanying disclosure and discussion.

Briefly stated, one preferred embodiment of my invention involves theuse of two similar chambers each containing a body of powdered catalyst,each chamber being used alternately onconversion and on reactivation,together with a third may be of any known type or may be omittedaltogether.A The size of the reactors may vary withinv wide 4limitsdepending upon the type of charge stock, catalytic contact time, amountof catalyst used, amount of catalyst circulated, and other knownfactors. For example, `the diameter may vary from 3 to 20 feet while theheight may vary from to 50 feet. A preferred reactor is 10 feet indiameter by 34 feet in height with a dished head and -a frusto-conicalbottom. In the topof each reactor, 3 and 4, aresituated-centrifugally-acting dust separators, 5, 6, 1 and 8, which maybe of the well-known cyclone type and -whose purpose is to rendersubstantially catalyst-free the gaseous streams leaving the reactors.Numeral II indicates a hopper for regenerated catalyst, cylindrical inform with a conical bottom, whose function is to serve as a catalystsurge tank as will be hereinafter explained. A dust separator, I2,similar in type and function to those located in the top of the reactorsis situated in the top of the catalyst hopper II to separate catalystfines from effluent reactivation product gas. The hopper should beadequately insulated in order to minimize cooling of the hot catalystcontained therein and may, if necessary, be equipped with reactivationgas distributing means 24 in its bottom to provide for eflcient contactof regenerating gas or hot spent regeneration gas with the temporarilystored catalyst. The furnace I5 is a steam and reactivation gaspreheater similar in design and function to the oil preheater I.

' For vthe purposes of this description it will be considered thatreactor 3 is on process ow while reactor 4vis on reactivation flowalthough it is to be understood that the reactors 3 and 4 actually arecyclically alternated on periods of process flow and regeneration flowso as to permit a continuous processing of hydrocarbons charged to theappa-V ratus. The hydrocarbon charge stock, selected from one or more ofthe types herein described, is charged to the conversion step throughthe line I6, pump I 1 and line I8 to the vaporizing coils 2 located inoil preheater I and thence through line I9, valve 20, line 2l, line 22and distributing means 9 to reactor 3. Immediately after reactivationreactor 3 contains from one-fourth to three-fourths, and preferablyabout one-half, of the total catalyst required for the process period tobe effected in reactor 3. Just before starting introduction of chargestock, the hot catalyst in reactor 3 may be and preferably is cooledsomewhat below the reactivation temperature by introduction of steamthrough line 25, preheater I5 (which may be by-passed for this purposeif desired), lines 26 and 21, valve 28, lines 2| and 22, and distributor9. This also serves to purge any oxygen from the catalyst bed. Suchstream is also used to maintain a fiuidized catalyst bed within thereactor during whatever period of time elapses between reactivation andconversion onstream periods. The hydrocarbons are cracked, or othercharge stock subjected to a desired reaction, in the fluidized catalystbed in reactor 3. Gaseous reaction products pass through cycloneseparator 5, line 29 (into which is introduced cool quench liquid fromvalved line 30), valve 3| and line 32 into fractionating column I3,wherein recycle stock plus entrained catalyst is recovered as a bottomsproduct for return to the process via lines 33 and I6, while gasolineand lighter products aretaken overhead via line 34 into stabilizingcolumn I 4. Light gases are removed through line 35 and thegasolineproduct is recovered through line" 36. ofcourse, units I3 and I4 maycomprise more than single fractionators, .'but the Various meansl ofhandling products and preparing materials for recycle are wellunderstood in the art and need not be discussed in further detail. t

Either immediately upon starting flow of gas oil vapors into. reactor 3,or after conversion has been effected .therein for a time, fresh hotrte--v activated catalyst (purged of residual reactivation 'gases' bysteam or by other conventional method not shown)A is -fed into thereactor, either directly by means not shown, or prefere' ably into theoil being charged, as by line 31, and catalyst flow rate control Valve38, into'line 2I which is carryinggthe preheated oil vinto the reactor,The thus-introduced catalyst provides additional preheat to bring theoil up to reactor inlet temperature and supply the endothermic heat ofreaction. An alternative, though usually less desirable, method is topass the catalyst re-' moved from the bottom of hopper II by way of line31 into the oilin line I8 ahead of preheater I, by means of Valve 39 andline '46.

During .most or all of the time, catalyst lis being thus removed fromhopper Il, additional catalyst is, being introduced into said hopperfrom the other reactorvli which is on regeneration, so that the catalystlevel in hopper II tends to stay fairly constant for the greater part ofeach cycle. The catalyst'in reactor 4, which is at apredetermined'maximum level When its reactivation isl initiated, isfirst purged of residual hydrocarbons. by passing 'steam therethroughand is then contacted with air from'line 4I, heater I5, lines 42 and 43,valve 44, line 45 and distributor I8. Steam may also be introduced fromline 26 through valve 46, line 41, and line `45 thence throughdistributor I0. Spent reactivation gases are passed through one or morecyclone separators 1 which recover most of the entrained catalyst andreturn it to the udized bed, and the'gases then pass through line 48,valve 49, line 50, 'line 5I, and line 52 into hopper Il, preferablytangentially to aid in separating any quantities of catalyst beingcarried in the gases. During all, or yonly the latter part, of'thereactivation period the gas velocity in reactor 4 is suiilciently highto carry partof the catalyst out of the fluidized bed by entrainment,and during such time valve 49 is closed and valve 53 in line; 54 is openso that cyclone separator 1 is by-passed.y Additional air can beintroduced Via line 43, valve 55, line 56, valve 51, and line 58 intoline 52 -for increasing gas velocity vin the latter conduit and/oreffecting further catalyst reactivation therein and yin hopper I I.Steam can also be supplied in the same manner by means of valve 59 andline 60. Alternatively or additionally, air and/or steam may bewithdrawn from line 56 by means of line 6I and valve B2 and passed intothe fluidized bed of catalyst in hopper I I by way of distributor 24toireactivate same further and/or to maintain same in fluidizedcondition. Reactivation gases ultimately pass through unit I2 whichcomprises one `or more cyclone separators and then out through line 63,Valve 64, cooler or heat exchanger 65, line 66 and valve 61 to vent 68;a portion may be recycled Via Valve 69, line 10, blower 1I and line 6Ito the distributor 24 to aid in fluidization.

When from half to two-thirds or even more of the catalyst has beentransported lout of reactor 4, the latter is ready to be purged and puton strearnfor; conversion. This is done Vas soon as reactor-3.hasz beenfilled with catalyst .modded to a predetermined maxi-mum .level 'andthat catalyst has been lused to 'the Adesired extent. The operation ofthe two .reactors is then reversed, so that rconversion is effected inunit -4 as described above with respect to unit 3., while unit 3 .is on.stream for :reactivation 1in `a manner similar :to that described abovewith respect 'to reactor f4. The use rof fthe various other .lines andvalves and other elements of equipmentrine cluding lines 72,., 123, Mand F15 Kcarrying valves 1.6, Tl, llland F19, respectively, will fbeobvious from vthe foregoing.

k"-Ihe following data are given as typical of the practice rof myinvention in Athe ycatalytic 'cracking of a gas oil to produce motortuoi. .First presented are specific figures ,for a single continuousrun, followed by a .recitation of. 'broader ranges lof conditionsyutilizable Lto'r isuch :a con version.. However, it .is 'to belunderstood that this information is by way -of exam-ple only, inas-much.as considerable variation .in flow rates, tempera-tures, quantities ofcatalyst, times .required Yfor Yconversion reactivation, and the like,may read-ily be .mlad'e by `one 'skilled in 'the are .in adapting the.principles vof the invention to given feed stocks, conversions,catalysts, and plant capa-cities.

Mid-Continent base vlstock of '38 A. P. I. vir gin gas oil with a 750 F.end-point is selected as a charging `stock for conversion to aIcornm-ercial motor-type gasoline. The process cycle is begun byv.pumping the selected .stock `to `an oil preheater at the rate of 250barrels -per .hour when Ait .is ,preheated from an .inlet temperaturelo'f 400 to Aan 'outlet temperature of 890 F. fat .an outlet 4pressureof about .12 pounds .per square inch rage. In order to assist in.heating the oil and minimize coke formation in the preheater., about420 pounds of steam per barrel of Joil is injected into the oil at amidpoint in the pre'- heater coil, The koil .preheater lis designed to.la-se sure almost complete vaporization vwith 'a .minimum residencetime and, consequently, ta mini-- mum of Vthermal fora-cking. (In manyinstances it is .preferred to :accomplish only partial vaporiza tion,with the .hot catalyst supplying :sufficient heat to complete thevaporization.) The vaporized charg stock is transferred to the bottom'of afoataflyti'creactor containing about 37,500 pounds of .newlyregenerated :acid-treated clay cracking catalyst of 150 microns averagediameter and 200 mesh maximum size distributed in fa bed 5 feet iindepth. The transfer lines between the .oil preheater and the catalyticreactor are sized to sgive 3.20 feet 'per :second vapor velocity `underthe cohditions .set forth above. The catalytic reactor is sized to allowfa .1.3-1.5 ieet per .second vapor ve locity through the catalytic massthereby .insuring 'a nuidized condition of 'the catalyst therein with aminimum of catalyst carryover.

The hot 'reactivated rcate'tlyst in lthe catalytic reactor is vrstcooled with steam to a temperature not much above the desired reactiontemperature, 'say down. to 925 F. The .reactor is operated at l poundsper square inch gage.. The converted hydrocarbon products are separate-dfrom the catalytic mass in the Alower part of the catalytic vreactorafter which they pass through a cyclone type dust remover wherein mostof the entrained catalyst is auto-centrifugally separated and returnedto the fluidized catalyst mass. The hydrocarbon vapors `are quenched to650"l F. immediately upon leaving the cyclone separator by injectingquench Water in-to the transfer line. The '650 F. vapors are then passedto .a fractionation step 'wherein the uneonverted charge stock boilingabove 4400" IF. .is separated .trom the llighter products, the #formerbeing returned with ent-rained catalyst as a .catalyst slurry recycletoftheoil preheater inlet. The lig'hterhydrocarbon ,products areseparated into butano-free 40.0 .-F. 'end-point gasoline and otherproducts-.including light .gases such as hydrogen, methane, ethylene andeethane, .and C3 and C4 params andoletins. Het (l1-50F.) reactivatedcatalyst is continuously added .from the catalyst hopper to thecatalytic reactor via th'e inlet hydrocarbon transfer line at the rateof 0.5 pound of catalyst per pound of oil. This addition maintains'theoverall activity Iof the catalyst the catalytic reactor at thl'e desiredlevel correspon-d ing to a per pass conversion of -50 per cent and., atthe sarne time., ipreheats the hydrocarbon feed from =890 to 925 therebyassu-ring a con stant v'and adequate reaction temperature above 900 and.below 925 F.

v When the reactor has been on stream for one hour, sunicient catalyst(about 37,500 pounds) has been added from the catalyst hopper to .ll thereactor to such a level that further addition is undesirable fan'd,hence, vtlf-ie reactor is removed from ,process duty for regeneration,the hydrocarbon charge being ldiverted to another catalytic reactor forcontinuing the conversion in a like manner as above.

The 7i5g000pounds of spent catalyst in the catalytic reactor after theone hour process ,period contains `3.0 weight vper cent carbon, which isremoved by oxidation. IAbout x340,000 cubic feet '(S. T. :P0 :per y'hourIof air compressed to 50 pounds per lsquare .in-ch gage rand 85,000pounds per hou-r of steam are mixed and preheated to 700 F. at 50 poundsper ysquare inch gage -in 'a reactiyation :gas pren-eater. The hotreactiva tion gas is throttled to 30 pounds per square inch gage andadmitted to -th-'e bottom of the catalytic reactor containing the spentcatalyst, and., as 'the gas .is passed upward through the reactor 4at avapor velocity of :lf3-11.5 feet per second, the catalyst .is maintainedin a fluidi-Zed condition enabling -a thorough 4burn-out of thedeposited carbon #at `a,fmaxirnu-m regeneration temperature of 1.150 F.The products for combustion are separated from .cntrained catalyst bycyclone sep arators situated .in t-he top of the reactor and in the topof the catalyst hopper after which they are `.passed .in heat lexchangerelationship with the .hydrocarbon charge stock Iand then released tothe air.

.After about 40 to 50 minutes of regeneration under the conditionsdescribed above, the carbon content of the catalyst has been reducedffrorn 3.0 to 0.3 `weight percent. VIn order to transfer 37,500 poundsofaccumulated vcatalyst from the reactor to the catalyst hopper, theeffluent regeneration `gas is by-passed around the cyclone separa-tor inthe top of the reactor directly to the catalyst hopper and theregeneration gas rate to the preheater .is then progressively .increasedto transport over tothe storage hopper 'the desired amount of thelcatalyst, i-.e-. 37,500 pounds. About 50:000gcubic .feet per hour ofair yand .123500 pounds per hourof steam, preheated as fa mixture .to70.09F.. are'alsoinj-eoted into the bottomof the catalyst :hopper 'and.into the catalyst trans fer .line between the reactor 'and the hopperto insure fan `adequate catalystecarrying vapor ve locity thereinand toycomplete the combustion of carbon .remaining on the catalyst. Thisaddi*- tional burning also vinsures the .maintenance .of

the desired"1150 F; catalyst l'temperature in the catalyst hopper. Thenal carbon content of the reactivatedcatalyst is 0.2 weight per cent. Asthis reactivation is going on,v catalyst is being fed from thereactivated catalyst hopper into the other converter wherein thecracking' reaction is continuing. Such reactivated catalystis purgedwith steam before being passed tothe converter. When reactivation iscompleted, the iiow 4of air is cut off and the reactor, vas well as thereactivated catalyst hopper if desired, is purged with steam prior toreintroduction of hydrocarbon feed thereto.

It Will be appreciated that the foregoing data represent only onepreferred set of conditions for use in catalytic cracking of gas oil.Other suitable cracking stocks include allv heavy residual oils such asvirgin and cracked gas oils or topped crude oils; such stocks may boilWithin the range of 400 to 1000 F. and higher, and will usually have agravity ranging from 20 to 40 A. P. 1. Cracking temperatures depend to acertain extent on the particular charge stock and catalyst used, andrange from 850 to 1100 F. From 0.5 to parts of catalyst per part (byweight of oil may be used. While any of the known cracking catalysts maybe employed, the synthetic and natural composites of silica with minoramounts of alumina are preferred; bauxite is also an effective anddesirable catalyst. Catalyst is used in the form of a powder, which termincludes any particle size such that the catalyst may be kept suspendedin gases in the reactor and reactivation as described. The length of onecomplete cycle may vary from one hour or less to 10 hours or more,depending largely on the amount of carbon laid down on the catalyst.This latter gure will be from one to 10 per cent by weight of thecatalyst for most oils and condtions of cracking.

`Inasmuch as the selection of specific catalysts, and specificconditions for reaction and for cafalyst reactivation, is well withinthe skill of the art forlany particular conversion or treatment, it isnot necessary to specify same in further detail here. The principles ofthe invention are applicable to any process wherein a carbonaceous fluidis contacted with a solid contact material under conditions causingdeposition thereon of carbonaceous matter which is removable by `oki-'-dation. Though the invention has been described by particular referenceto preferred embodiments, changes may be made by those skilled in theartin the materials and conditions disclosed without departing from thescope of the invention as dened in the appended claims.

I I claim:

1. In the treatment of organic uids with va nely divided solid contactmaterial in which treatment carbonaceous matter is deposited on saidmaterial, is removed therefrom by oxidation, and the material is thenreused in said treatment, the improvement which comprises maintaining afluidized mass of said material within each of a plurality oftreatment-reactivation zones, maintaining a fluidized mass ofreactivated 4contact material within a storage zone, passing an organiciiuid to be treated into one of said treatment-reactivation zonescontaining a predeter-l mined minimum quantity of said-contact mateirial in a fluidi'zed state under conditions effecting the desiredtreatment, introducing into said zone additional' quantity ofreactivated contact material from said storage zone while passing saidfluid therethrough thereby 'gradually increasing 152 theouantityrfeontact material within said zone while minimizing the averagecarbon content of the contact material therein, then when the quantityof contact material within said zone hasincreased to apredeterminedmaximum diverting the flow of uid to be treatedinto another of saidtreatment-reactivation zones containing a predetermined minimum quantityof contact material therein, continuing. the treatment in said otherzonein the manner just described with introduction of reactivatedcontact material thereint from the said storage Zone, While continuingytreatment of said fluid in said another zone subjecting the contactmaterial in the iirst said zone' to reactivation .by passingtherethrough an oxidizing reactivation gas under conditions eiectingremoval of oarbonaceous matter from the contact material by oxidation,continuing said reactivation of the catalyst remaining in said' rst zonefor a suicient period of time to effect' a reduction of thecarbon'content to a desired extent, during said reactivation periodtransferring a substantial portion of the catalyst from said iirst zoneinto said storage zone to decrease the quantity of contact material insaid rst zone to the aforesaid predetermined minimum, and thereafterpassing said fluid to be treated into said first zone for treatmenttherein and repeating the cycle as described. 2. The method of claim 1in which said contact material is transferred from said firsttreatment-reactivation zone into said storage zone by increasing theArate of flow of gases upwardly through said rst zone to carry contactmaterial in suspension therein, and recovering the thus-suspendedcatalyst from the gaseous effluent from said first zone and accumulatingthe thusrecovered contact material in said storage zone.

3. The method of claim 2 in which the suspension of contact material ineilluent reactivation gases is passed into said storage zone forseparation of the contact material therein, and in which additionalquantities of oxidizing reactivation gases are introduced into saidsuspension at a point between the said first zone and the said storageZone for effecting further oxidation of carbonaceous matter from saidsuspended -contact material;

4. The method of claim 2 in which contact material accumulated in saidstorage zone is subjected to further reactivation by passage ofoxygen-oxidizing reactivation gases through the contact materialmaintained in a iiuidized condition in said zone.

5. The method of claim 1 in which a pair of said treatment-reactivationzones and a single contact material storage zone are employed, each saidtreatment-reactivation zones being alternately on-stream for treatmentand on-stream for reactivation. v

6. The method of claim 1 in which a hydrocarbon fluid is subjected toconversion conditions in the presence of a solid contact catalyst.

'7; A process for cracking hydrocarbon oils Which comprises vaporizing ahydrocarbon oil and passing same upwardly through a first tur-4 bulentmass of powdered cracking catalyst at' cracking conditions oftemperature, pressure'andy contacttime, separating gaseous crackingproducts from said mass, continuing for a period of time until thequantity of carbonaceous material deposited on the catalyst in said massattains a' predetermined maximum, during said periodfintroducing intosaid mass additional quantities of hot reactivatedfpowdered crackingcatalyst tov minimize loss of catalyst activity therein, at the end ofsaid period passing said vaporized oil in contact with a second mass ofpowdered cracking catalyst in the manner just described, purginghydrocarbons from the AFirst named mass and then passing therethrough ahot oxygen-containing gas under conditions effecting reactivation of thecatalyst by oxidation of carbonaceous matter therefrom, during thethus-described reactivation treatment increasing the velocity ofreactivation gases to eiiect entrainment of a substantial proportion ofthe catalyst mass as a suspension of catalyst particles in hot gases,separating the thus-suspended particles from the hot gases andaccumulating same in a third mass of catalyst particles maintained in afluidized condition by upward iiow of iiuidizing gases therethrough,utilizing said third mass of catalyst as the source of theaforementioned additional quantities of hot reactivated catalystintroduced into the masses of catalyst employed for cracking said oil,purging said hydrocarbons from said second mass of catalyst at the endof its cracking period, again utilizing for cracking the iirst said massof catalyst which has been reactivated and reactivating the said secondmass of -catalyst in the manner described, and continuing the aforesaidprocess cyclically with each said first and second masses of catalystbeing employed alternately for cra-cking and reactivation.

8. The process of claim 7 wherein hot reactivated catalyst from saidthird mass of catalyst is continuously supplied to the vaporized oilprior to its introduction into a mass of catalyst for cracking duringeach entire cracking period,

9. The process of claim 7 in which each said first and second masses of-catalyst is used for cracking for a part of the cracking period withoutintroduction thereto of any hot reactivated catalyst from said thirdmass, and in which the balance of the cracking period is carried outwhile introducing said hot reactivated catalyst to said mass.

10. The process of claim 7 in which the said rst and second masses ofcatalyst are cooled from reactivation temperature to crackingtemperature prior to introduction of vaporized oil thereto. y

11. In the treatment of fluids With a finely divided solid contactmaterial in which treatment the contact material becomes fouledresulting in decreased activity, the fouled conta-ct material isreactivated, and the reactivated material is then reused in saidtreatment, the improvement Which comprises maintaining a fluidized massof said material Within each of a plurality of treatmentreactivationzones, maintaining a fluidized mass of reactivated contact materialwithin a storage zone, passing a iiuid to be treated into one of saidtreatment-reactivation zones containing a predetermined minimum quantityof said contact material in a fluidized state under conditions effectingthe desired treatment, introducing into said zone additional quantity ofreactivated contact material from said storage zone While passing saidiiuid therethrough thereby gradually increasing the quantity of contactmaterial within said zone While minimizing the loss in activity of thecontact material therein, then When the quantity of contact materialWithin said zone has increased to a predetermined maximum diverting theflow of fluid to be treated into another of said treatment-reactivationzones containing a predetermined minimum quantity of contact materialtherein, continuing the treatment in said other zone in the manner justdescribed with introduction of reactivated contact material thereintofrom the said storage zone, while continuing treatment of said iiuid insaid another zone eifecting reactivation of the contact material in therst said zone by subjecting same to conditions effecting removal offouling material therefrom, continuing said reactivation of the Contactmaterial remaining in said rst zone for a sufficient period of time toreactivate same to a desired extent, during said reactivation periodtransferring a substantial portion of the contact material from saidfirst zone into said storage zone to decrease the quantity of contactmaterial in said first zone to the aforesaid predetermined minimum, andthereafter passing said fluid to be treated into said rst zone fortreatment therein and repeating the cycle as described.

BURLE F. WOBKER.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 2,268,187 Churchill Dec. 30, 19412,392,957 Thomas Jan. 15, 1946 2,413,271 Warrick Dec. 24, 1946 2,421,616Hemminger et al. June 3, 1947 2,435,158 Read Jan. 27, 1948

